JPS6126942B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a rubber-containing asphalt composition for road paving, and more specifically, it relates to a rubber-containing asphalt composition for road paving, and more specifically, a rutted moat composition made of asphalt and a conjugated diene rubber (latex) having a polar group and a specific Mooney viscosity. This invention relates to an improved rubber-containing asphalt composition for road paving. Conventionally, in order to compensate for the various drawbacks of asphalt pavement, a paving material made by mixing asphalt with rubber has been used for road paving. Rubber with asphalt (and/or tar)
When mixed with asphalt, the temperature sensitivity of asphalt decreases, adhesion with aggregate and resistance to abrasion increase, and the properties of asphalt pavement at low temperatures are significantly improved by adding flexibility. .
Furthermore, at high temperatures, it is more stable (in terms of fluidity) and has improved impact resistance. Asphalt containing rubber thus has many advantages. However, due to the increase in traffic volume and weight, in heavy traffic areas, uphill lanes, near intersections, etc., the paved road surface may undergo flow deformation such as ruts, flow, and waves within a short period of time after paving. A phenomenon occurs,
Vibrations caused by running vehicles not only impede safe driving of vehicles, but also cause vibration pollution to residences around roads, and a solution to this problem is desperately needed. Traditionally, in this field, styrene-butadiene copolymer rubber with a Mooney viscosity (ML ₁₊₄ , ₁₀₀ °C) of about 30 to 100 has been mainly used, but asphalt compositions containing this rubber do not meet the above requirements. Unable to satisfy the above requirements, the present inventors conducted extensive studies to develop a new rubber-containing asphalt composition for road paving, and as a result, they arrived at the present invention. The object of the present invention is to provide an asphalt pavement composition with improved rutting, which has a specific Mooney viscosity (ML ₁₊₄ , ₁₀₀ °C) for asphalt; This is achieved by using a composition containing a conjugated diene rubber containing a specific polar group. The use of the conjugated diene rubber of the present invention also has the advantage of improving workability. The asphalt used in the present invention may be any commonly used asphalt, such as straight asphalt for pavement, natural asphalt such as lake asphalt, semi-blown asphalt, straight asphalt modified with a part of blown asphalt, tar-modified straight asphalt, etc. included. The polar group-containing conjugated diene rubber (latex) of the present invention is obtained by a normal polymerization method and contains (1) 50 to 99.5% by weight of a conjugated diene monomer, and (2) an amide group, an amino group, or an N-methylol group. A copolymerizable vinyl monomer having a polar group selected from the group consisting of , carboxyl group, hydroxyl group, and glycidyl group.
Mooney viscosity (ML ₁₊₄ , ₁₀₀ °C) obtained by copolymerizing 0.5 to 10% by weight and (3) 49.5 to 0% by weight of a copolymerizable vinyl monomer other than the above (total of 100 parts by weight of all monomers) is at least 50 copolymer rubber. The use of a vinyl monomer having a polar group as described above is essential in order to exhibit the effects of the present invention; if it is less than 0.5% by weight, no improvement in ruts can be obtained, and if it exceeds 10% by weight, the effect is saturated. At the same time, the asphalt viscosity increases, making workability worse. Preferably it is 1 to 5% by weight. Examples of vinyl monomers having an amide group include acrylamide, methacrylamide, maleamide, etc.; examples of monomers having an amino group include:
Vinylpyridine, N-N'-dimethylaminoethyl acrylate, etc., monomers having an N-methylol group include N-methylol acrylamide, N-methylol methacrylamide, etc., monomers having a carboxyl group include acrylic acid, methacrylic acid, etc. , itaconic acid, crotonic acid,
Examples of monomers having a hydroxyl group include allyl alcohol, 2-hydroxyethyl acrylate, 2-hydroxypropyl methacrylate, and 2-hydroxybutyl acrylate; examples of monomers having a glycidyl group include glycidyl acrylate, glycidyl methacrylate, and acrylic glycidyl ether. These include, but are not limited to. At least 50% by weight of the conjugated diene monomer is required in order to balance various physical properties. Preferably it is 65 to 80% by weight. Conjugated diene monomers include butadiene, isoprene, 1,3-pentadiene, chloroprene, and the like. The amount of the vinyl monomer other than the component (2), which is the component (3) and can be copolymerized with the components (1) and (2), is
The content is 49.5% by weight or less, and if it exceeds this, the elasticity decreases, which is not preferable. Preferably it is 30-19% by weight. Monomers for component (3) include vinyl aromatic compounds such as styrene, α-methylstyrene, and vinyltoluene, vinyl cyanide compounds such as vinyl acetate, acrylonitrile, and methacrylonitrile, methyl methacrylate, methyl acrylate, and dimethyl maleate. Includes ethylenically unsaturated carboxylic acid esters such as esters. The desired polar group-containing conjugated diene rubber (latex) can be obtained by copolymerizing the monomers (1) to (3) above using a conventional polymerization method, such as emulsion polymerization. The Mouni viscosity (ML ₁₊₄ at ₁₀₀ ° C.) of the rubber must be at least 50; if it is less than 50, the object of the present invention will not be achieved even if polar groups are present in the rubber. Preferably it is in the range of 70-150. Even if it is 150 or more, the object of the present invention can be achieved, but the viscosity of the rubber-containing asphalt becomes high and workability deteriorates. Conventionally used styrene-butadiene copolymers that do not contain polar groups have the disadvantage that when the Mooney viscosity exceeds 70, the viscosity of rubber-containing asphalt increases and workability deteriorates, but the polar group-containing copolymer of the present invention Rubber has the advantage that even if the Mooney viscosity is increased, the asphalt viscosity does not increase and workability is excellent. The copolymer rubber of the present invention can be added to asphalt in the form of latex or solid rubber, but it is usually added in the form of latex. The amount of the copolymer rubber added to the asphalt is 1 part by weight or more, preferably 2 to 10 parts by weight of the copolymer rubber of the present invention based on 100 parts by weight of the asphalt, depending on the type of asphalt used. . Generally, asphalt road paving compositions consist of aggregates such as crushed stone and sand, fillers such as stone powder, lime, etc., and asphalt, and 88 to 96% by weight of the composition is aggregate and filler, and 4 to 12% by weight. is asphalt. The asphalt road paving composition is produced by a conventional method for producing the composition, for example, asphalt, crushed stone, sand, stone powder, etc. are kneaded in a mixer of an asphalt plant, and rubber latex is added using a pump or the like to form a rubber-containing asphalt mixture. Manufactured by a manufacturing method etc. The present invention will be specifically explained below using Examples. Example Aggregate composition, No. 5 crushed stone 15.2% by weight, No. 6 crushed stone 24.6%
Weight%, No. 7 crushed stone 9.5% by weight, coarse sand 18.0% by weight,
20.8% by weight of medium-grained sand, 94.7% by weight of aggregate consisting of 6.6% by weight of stone powder, and 5.3% by weight of straight asphalt (penetration 60-80), which is normally used for pavement.
Furthermore, the conjugated diene rubber latex having polar groups of the present invention was added to the straight asphalt in an amount of 4%.
(in terms of solid content) were mixed at a temperature of 170 to 180°C to obtain a mixture of dense-grained asphalt concrete. This mixture was heated to 160℃ using a roller compactor.
A specimen for the compaction wheel tracking test was prepared. The wheel tracking test was conducted according to the British Road Research Institute's test method. The test temperature was 60°C, the wheel pressure was 6.4Kg/cm ² and the corresponding wheel load was 10 tons. Dynamic stability is calculated by the number of travels per 1 mm deformation (times/
mm), and there is a correlation between the number of trips and ruts, and the greater the number of trips, the less likely ruts will occur. Next, asphalt viscosity test at 60℃
The test was carried out using a reduced pressure capillary viscometer according to JAA-001 (JAA is the Japan Asphalt Association Test Method).
For sample preparation, the same straight asphalt as described above was heated and stirred at 160° C., and 4% of the solid content of the conjugated diene rubber latex having a polar group of the present invention was added and mixed to the asphalt to prepare a sample. Comparative Example A dense-grained asphalt concrete mixture was prepared in the same manner as in the example using the asphalt used in the example, the conjugated diene rubber latex of the comparative example shown in Table 1, or a similar latex having a polar group, and compacted at 160°C. A similar specimen was prepared and the dynamic stability was measured. In addition, the asphalt viscosity at 60° C. was also measured in accordance with JAA-001 in the same manner as in the examples.
The results are shown in Table 1. Production example of latex 30 parts of styrene, 62 to 70 parts of butadiene, 0 to 8 parts of the polar group-containing monomer listed in Table 1, 0.5 part of sodium carbonate, 0.4 part of sodium sulfate, 0.3 part of potassium persulfate,
A mixture of 0.2 to 1.0 parts of grade dodecyl mercaptan and 1.5 parts of sodium lauryl sulfate was placed in a 10 autoclave and reacted with stirring at 50°C for 10 to 25 hours to prepare the polymer latex shown in Table 1.

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Claims (1)

[Claims] 1 Based on asphalt, (1) conjugated diene monomer 50 to 99.5% by weight, (2) amide group, amino group, N-
0.5 to 10% by weight of a copolymerizable vinyl monomer having a polar group selected from the group consisting of a methylol group, a carboxyl group, a hydroxyl group, and a glycidyl group; (3) 49.5 to 0% by weight of a copolymerizable vinyl monomer other than the above. A rubber-containing asphalt composition for road paving, characterized in that it contains a polar group-containing conjugated diene rubber having a Mooney viscosity (ML ₁₊₄ , ₁₀₀ ° C.) of at least 50, which is obtained by copolymerizing the following.